It is well known that development of conformational structure depends on amino acid sequence, although the exact relationship, which would make possible a reliable prediction of native conformation from a knowledge of primary structure, remains unclear. The native conformation develops from the randomly coiled chain of the denatured (or newly synthesized) protein through the influence of many interactive forces, including "nucleation", whereby a transition to the native conformation occurs concommitantly with formation of SS bonds. The role of SS bonds in this process is not well understood, but it is generally assumed that they have a stabilizing function, rather than a positive influence on structure formation. Recent work in this laboratory questions this assumption, and further work is in progress to clarify the role of SS bonds in chain folding.